Method and apparatus for forming convoluted metal annulus

ABSTRACT

A method and apparatus for forming a radially convoluted annulus from a cylindrical blank of sheet metal. The convoluted annulus may be used in disc brake assemblies, for example. Two circular sets of individually pivoted forming tools initially grip the cylindrical blank on opposite sides thereof, and are then pivoted inwardly to convert the cylinder to an annulus which may be either flat or tapered. At the same time, the two sets of forming tools are advanced relatively toward each other so as to form radial convolutions in the metal blank. The pivotal movement of the two sets of forming tools is controlled by hydraulically actuated cams.

United States Patent 1 F encl et al.

[54] METHOD AND APPARATUS FOR FORMING CONVOLUTED METAL ANNULUS [75] Inventors: Vernon R. Fencl, Northbrook; Al-

bert Roze, Chicago, both of 111.

[73] Assignee: Grotnes Machine Chicago, Ill.

[22] Filed: Feb. 14, 1972 [21] Appl. No.: 226,057

Works, Inc.,

[ June5,1973

2,485,969 10/1949 Johnson ..72/370 FOREIGN PATENTS OR APPLlCATlONS 726,449 10/1931 France ..72/367 Primary Examiner-Charles W Lanham Assistant Examiner-M. J. Keenan A ttorney-C. Frederick Leydig, Richard L. Voit and Stephen G. Rudisill et al.

[57] ABSTRACT A method and apparatus for forming a radially convoluted annulus from a cylindrical blank of sheet metal. The convoluted annulus may be used in disc brake assemblies, for example. Two circular sets of individually pivoted forming tools initially grip the cylindrical blank on opposite sides thereof,.and are then pivoted inwardly to convert the cylinder to an annulus which may be either flat or tapered. At the same time, the two sets of forming tools are advanced relatively toward each other so as to form radial convolutions in the metal blank. The pivotal movement of the two sets of forming tools is controlled by hydraulically actu ated cams.

6 Claims, 16 Drawing Figures PATENTEDJUN 5 I973 SHEET 1 [IF 5 PATENTEDJUH 5 1915 3.736, 787

SHEET 3 [IF 5 VIII. I II III! METHOD AND APPARATUS FOR FORMING CONVOLUTED METAL ANNULUS DESCRIPTION OF THE INVENTION The present invention relates generally to metal forming methods and apparatus and, more particularly, to an improved method and apparatus for forming a radially convoluted metal annulus of the type used in disc brake assemblies and the like.

It is a primary object of the present invention to provide an improved method and apparatus for forming a radially convoluted metal annulus from a cylindrical blank open at both ends.

Another object of the invention is to provide such an improved metal forming apparatus that is capable of forming the convoluted metal annuli rapidly and efficiently to achieve high production rates.

A further object of the invention is to provide an improved method and apparatus of the foregoing type that forms the convoluted metal annuli without any scrap and with minimum elongation of the metal in the starting blank.

Still another object of the invention is to provide such an improved method and apparatus that is capable of producing either fiat or tapered convoluted annuli, and with different degrees of convolution.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings, in which:

FIG. I is a perspective view of a metal forming machine embodying the invention;

FIG. 2 is a perspective view of a blank for use in the machine of FIG. 1;

FIG. 3 is a perspective view of a convoluted annulus formed by the machine of FIG. 1, starting with the blank shown in FIG. 2;

FIG. 4 is an enlarged section taken along line 4-4 in FIG. I, with the movable parts in a first operative position;

FIG. 5 is the same section shown in FIG. 4 with the movable parts in a different operative position;

FIG. 6 is a fragmentary section of the same equipment shown in FIGS. 4 and 5 with the movable parts in still another different operative position;

FIG. 7 is an enlarged section taken along line 7-7 in FIG. 4;

FIG. 8 is an enlarged section taken along line 8-8 in FIG. 4;

FIG. 9 is an enlarged perspective view of one of the individual forming tools .in the equipment of FIGS. 4-8;

FIG. 10 is an enlarged perspective view of a different individual forming tool in the equipment of FIGS. 4-8;

FIG. 11 is an enlarged section taken along line 1l-11 in FIG. 5;

FIG. 12 is an enlarged section taken along line 12-12 in FIG. 5;

FIG. 13 is a schematic diagram of the metal forming operation effected by the machine of FIG. 1 wherein the convoluted peripheries A and B of the formed part are approximately equal to the peripheries A and B of the starting cylindrical blank;

FIG. 14a is a partial plan view of the convoluted annulus shown in FIG. 3;

FIG. 14b is a partial elevation of the inner periphery of the annulus shown in FIG. 13a;

FIG. 14c is a partial elevation of the outer periphery of the annulus shown in FIG. 130.

While the invention will be described in connection with certain preferred embodiments, it is to be understood that the invention is not limited to these particular embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention.

Turning now to the drawings, the machine shown in FIG. 1 is adapted to receive a cylindrical metal blank 10 as illustrated in FIG. 2 and automatically form it into a convoluted annulus 11 as illustrated in FIG. 3. The convoluted annulus 11 may be used, for example, as a cooling member between two discs in a disc brake assembly. The metal forming elements in the machine of FIG. 1 are supported by a stationary frame 12 connected to a rigid bed 13 having a cylindrical section 12a extending laterally from one side thereof.

In accordance with one important aspect of the invention, the cylindrical blank 10 is placed between a pair of opposed annular tool means adapted to bend one edge of the blank radially inwardly about the other edge while convoluting the blank along a multiplicity of spaced radial lines. Thus, in the illustrative arrangement a first circular array of outer forming tools 14 is disposed concentrically around a second circular array of inner forming tools 15. The forming surfaces of the inner and outer tools 14 and 15 are all identical to each other, (see FIGS. 9 and 10), but the tools in the two circular arrays are circumferentially offset from each other so that the tools in the outer circle mesh with the tools in the inner circle as the two sets of tools are advanced relative to each other.

As can be seen most clearly from the enlarged perspective views of the two forming tools in FIGS. 9 and 10, each individual tool includes an elongated rounded head portion 14a or 15a which defines the cross sectional configuration of the convolutions in the annulus 11. Since the circumferential width of each radial section of the annulus 11 increases from the inner periphery to the outer periphery of the annulus, the circumferential thickness of the head portions 14a and 15a of the respective forming tools 14 and 15 also increases from one end of the forming tool to the other. Consequently, the circumferential width of the convolutions formed by the tools 14 and 15 also increase from the inner periphery to the outer periphery of the annulus 11. The forming tools 14 and 15 are positioned in the machine so that the minimum thickness ends of the opposed tools are aligned with each other at the end of the metal blank corresponding to the inner periphery of the final annulus 11, while the maximum thickness ends of the tools are aligned with each other at the end of the metal blank corresponding to the outer periphery of the annulus 1 1. It will be appreciated that any desired number of forming tools may be included in each circular array, depending on the number of convolutions desired in the final product. Similarly, the tools may be provided with heads of any desired shape, according to the desired configuration of the convolutions in the final product.

For the purpose of mounting the outer forming tools 14 on the cylindrical frame section 12a, each tool 14 is bolted to an outer tool arm 20 which is pivotally mounted on a radial guiding and support member 21 recessed within the end portion of the frame section 12a. All the members 211 for the entire circle of tool arms 20 are bolted to a common annular retainer ring 22 fastened to an annular end wall 12b of the stationary frame section 12a. More specifically, each outer tool arm 24B is bifurcated (see FIG. 8) to fit over one of the members 21 so that the arm 2th is not only supported by, but also guided by, the member 21. It will be understood that each of the outer tools 14 is carried by a separate arm 20 which is pivotally mounted on a separate supporting and guiding member 21 so that the tools 14 are all movable independently of one another.

The supporting structure for the inner forming tools i is similar to that of the outer tools 14. Thus, each inner tool 15 is bolted to an inner tool arm 23 pivoted on a radial supporting and guiding member 24 recessed within the end portion of the frame section 12a. Each tool 15 is carried by its own separate arm 23 pivoted to its own separate supporting and guiding member 24, with all of the supporting and guiding members 24 being bolted to the same retaining ring 22 that holds the supporting and guide members 21 for the outer tool arms 20.

As in the case of the outer tool arms 20, each inner tool 23 is bifurcated (see FIG. 8) to fit over one of the radial members 24. Thus, it can be seen that each of the individual forming tools 14 and 15 in the two circular sets of tools is mounted for independent pivotal movement along a radial path determined by the supporting and guiding member 21 or 24 which carries the tool arm. The radial paths for all the forming tools 14 and 115 in the two circular sets emanate from a common center point, since the supporting and guiding members 211 and 24 all extend along radii projected from the single circular retaining ring 22.

When the cylindrical metal blank is inserted into the machine, the outer tools 14 are in the position illustrated in FIGS. 4 and 6, which will be referred to hereinafter as the outer position, while the inner forming tools ll5 are in the position illustrated in FIGS. 5 and 6, which will be referred to hereinafter as the inner position. The cylindrical blank llilt has an outside diameter substantially equal to, or slightly less than, the diameter of a circle connecting the radially innermost surfaces of the outer forming tools 14 in their outer positions, and is inserted axially along the surfaces of the tool heads Ma until the blank abuts radially inwardly projecting stops 25 formed on the rear ends of the outer tools 14. Thus, the stops 25 position the blank lit) in the axial direction. As can be seen most clearly in FIGS. 4-6, The length of each outer forming tool 14 is slightly greater than the axial length of the blank 10, so that the forward ends of the tools H4 extend slightly beyond the cylindrical blank it) when the blank is positioned against the stops 25.

After the blank 110 is inserted into the machine, an inner cylindrical cam 30 is advanced in the axial direction over the inner surface of the frame section 123., from right to left as viewed in FIGS. 4-6, by means of a hydraulic actuator 31 mounted on the stationary frame H2. As the cam 30 is advanced, the forward end thereof acts on a cam follower 32 on each of the inner tool arms 23 to pivot the arms 23 from their inner positions (FIIGS. 5 and 6) to their outer positions (FIG. 4). It will be appreciated that the cam 30 acts on the cam followers 32 of all the inner tool arms 23 simultaneously, so that the entire inner circle of tool arms 23 is pivoted outwardly at the same time. As the inner tool arms 23 reach their outer positions, the inner forming tools 15 engage the inner surface of the cylindrical blank 10 so that the blank is firmly gripped between the two circular sets of tools 14 and 15. As can be seen most clearly in FIGS. 4-6, the pivot points of the outer and inner arms 20 and 23 are offset by a distance t equal to the radial thickness of the blank it) so'that the opposed tool heads 14a and 15a lie flat against the opposite sides of the blank 10 when the tool arms are both in their horizontal outer positions (FIG. 4).

At this point, the forming 'of the blank if is initiated by advancing an outer cylindrical cam 40 in the axial direction over the outer surface of the frame section 12a, from right to left as viewed in FIGS. 4-6, by means of a pair of hydraulic actuators 41 and 42 mounted'on the vertical section of the stationary frame 12. As the cam 40 is advanced, the leading end thereof acts on a pair of cam followers 43 on each of the outer tool arms 20 to pivot the arms 20 from their outer positions (FIGS. 4 and 6) to their inner positions (FIG. 5). It will be appreciated that the cam 40 acts on the cam followers of all the outer tool arms 20 simultaneously, so that the entire outer circle of tool arms 20 is pivoted inwardly at the same time. This pivotal movement of the outer tool arms 20 is resisted not only by the stiffness of the metal blank 10, but also by the internal resistance of the hydraulic actuator 31 connected to the inner cam 30 bearing on the inner tool arms 23. HOW- ever, the hydraulic actuators 41 and 42 for the outer cam 40 are designed to have sufficient power to overcome all of these resisting forces, so that the movement of the outer tool arms 20 from their outer to their inner positions bends the left end of the metal blank 10 about the right end thereof, (as viewed in FIGS. 4-6), while at the same time moving the inner tool arms 23 from their outer positions to their inner positions. This movement of the outer tool arms 20 is continued through an arc of so that the tools reach the positions illustrated in FIG. 5, where the blank 10 is deformed so that the two ends thereof lie in the same radial plane. Thus, the original axial width of the cylindrical blank 10 becomes the radial width of the final annulus 11. If it is desired to produce a tapered annulus rather than a flat annulus, the tool arms 20 are pivoted through an arc of less than 90 degrees to provide the desired degree of taper.

' In accordance with one particular aspect of the invention, the inner and outer tools 14 and 15 are advanced toward each other during the pivotal movement thereof so that the inner and outer forming tools 15 and 14 overlap each other to form radial convolutions in the metal blank 10. Thus, in the illustrative embodiment, the pivot points for the inner and outer tool arms are axially offset from each other in the horizontal direction by a distance equal to the difference between the radii r, and n. Consequently, as the forming tools 14 and 15 are rotated from their outer horizontal positions illustrated in FIG. 4 to their inner vertical positions illustrated in FIG. 5, the opposed heads 14a and 15a of the forming tools are advanced relatively past each other by the distance (r, r,), so that the meshing of the two sets of forming tools deforms the metal blank 10 in a convoluted pattern corresponding to the profiles of the tool heads 14a and 11511. This convoluting deformation of the metal blank takes place simultaneously with the deformation of the blank from its cylindrical shape of FIG. 2 to the relatively flat annular shape of FIG. 3, thereby converting the cylindrical blank to a convoluted annulus in one simple, quick operation.

The deformation of the metal blank from its original cylindrical form to its final annular form is illustrated in FIG. 13, from which it can be seen that end A of the blank is bent radially inwardly about end B, while end B is moved radially inwardly through the distance r,,. The bending of end A about end B forms a truncated cone with an increasing apex angle and decreasing base and top diameters. The gradual reduction in the diameter of the blank is necessary to compensate for the increasing amount of metal taken up by the radial convolutions that are being formed in the blank simultaneously with the bending of end A about end B. Thus, while end A of the blank is being bent about end B, the blank is also being convoluted by the gradual overlapping of the tools 14 and 15 until they reach their fully meshed positions as shown in FIGS. 5 and 12. To effect the convolutions, the resistance offered by the inner tools 15 (due to their actuator 31) to the inward movement of the tools 14 is greater than the resistance of the metal blank 10, so that the two sets of tools 14 and 15 gradually move toward each other during their pivotal movement. The fully meshed positions of the tools 14 and 15, when both sets of tools are in their inner positions as shown in FIG. 5, are illustrated in FIG. 12, while the configuration of the convolutions formed thereby is best illustrated in FIGS. 14a-c. The exact dimension of the final depth d of the convolutions is determined by the inter-related geometry of the tool profiles and the radii r and n.

It will be appreciated that the offset (r r of the pivot points for the inner and outer tools 15 and 14 causes the outer tools 14 to be displaced radially outwardly relative to the inner tools during the pivotal movement thereof. To accomodate this radial displacement of the two sets of tools, the inner tools 15 are slightly longer than the outer tools 14 in the radial direction, so that the stops 25 on the outer tools simply slide the blank radially outwardly over the inner tools during the pivotal movement thereof.

To form a tapered annulus instead of a flat annulus, the pivotal movement of the tools 14 and is stopped at a position intermediate the horizontal and vertical positions illustrated in FIG. 13. In this case, the pressure in the actuator 31 for the inner cam 30 is increased prior to termination of the advancing movement of the outer cam 40 so that the forming tools 14 and 15 reach their fully overlapped or meshed positions (FIG. 12) to form convolutions of maximum depth d in the tapered annulus.

When the two sets of forming tools reach their inner positions, the outer cam 40 is retracted by its actuating cylinders 41 and 42 so that a return cam 50 bolted to the front end of the cam 40 acts on the cam followers 43 to return the outer tool arms to their outer positions. The return cam 50 forms a series of radial slots 50a around the inner periphery thereof for receiving moval of the convoluted annulus 11 and insertion of corresponding arcuate ribs 200 extending radially outwardly from, and formed as integral parts of, the outer tool arms 20; as the arms 20 are pivoted inwardly and outwardly by the cams 40 and 50, the ribs 20a slide back and forth within the slots 50a so as to guide and stabilize the arms 20 in the lateral or circumferential direction. While the outer tool arms 20 are returned to their outer positions, the inner tool arms 23 remain in their inner positions, so that the two sets of forming tools are separated from one another to facilitate rethe next blank 10 into the forming machine. Thus, the machine has been returned to its original starting condition (FIG. 6) and is ready to repeat another cycle of operation.

We claim as our invention:

1. Apparatus for forming a radially convoluted annulus from a cylindrical blank of sheet metal, said apparatus comprising the combination of a pair of opposed annular tool means mounted for movement toward and away from each other and having cooperating faces adapted to mesh with each other to form convolutions in a sheet of metal disposed therebetween, means for urging the opposed tool means toward each other for gripping said blank therebetween, means for pivoting the opposed tool means from a first position where the faces of said tool means are substantially horizontal for gripping said blank, to a second position spaced radially inwardly from said first position and where the faces of said tool means are disposed at a substantial angle to the horizontal whereby one edge of said blank is twisted radially inwardly about the other edge thereof, and means for advancing the opposed tool means toward each other during the pivotal movement thereof so that said tool means mesh with each other to form radial convolutions in said blank.

2. Apparatus as set forth in claim 1 wherein each of said tool means comprises a plurality of forming elements arranged in a circular array, said elements being elongated in the horizontal direction when said tool means are in said first position and in the radial direction when said tool meansare in said second position.

3. Apparatus as set forth in claim 1 wherein each of said forming elements is mountedfor pivotal movement along a radial path.

4. Apparatus as set forth in claim 1 wherein the faces of said opposed tool means are substantially vertical in said second position.

5. Apparatus as set forth in claim 1 wherein said opposed tool means are independently mounted for pivotal movement about spaced pivot points having a vertical spacing about equal to the thickness of said blank and a horizontal spacing about equal to the depth of the convolutions formed in said blank.

6. Apparatus as set forth in claim 1 wherein said means for urging said opposed tool means toward each other comprises hydraulic actuating means.

i I I! i i 

1. Apparatus for forming a radially convoluted annulus from a cylindrical blank of sheet metal, said apparatus comprising the combination of a pair of opposed annular tool means mounted for movement toward and away from each other and having cooperating faces adapted to mesh with each other to form convolutions in a sheet of metal disposed therebetween, means for urging the opposed tool means toward each other for gripping said blank therebetween, means for pivoting the opposed tool means from a first position where the faces of said tool means are substantially horizontal for gripping said blank, to a second position spaced radially inwardly from said first position and where the faces of said tool means are disposed at a substantial angle to the horizontal whereby one edge of said blank is twisted radially inwardly about the other edge thereof, and means for advancing the opposed tool means toward each other during the pivotal movement thereof so that said tool means mesh with each other to form radial convolutions in said blank.
 2. Apparatus as set forth in claim 1 wherein each of said tool means comprises a plurality of forming elements arranged in a circular array, said elements being elongated in the horizontal direction when said tool means are in said first position and in the radial direction when said tool means are in said second position.
 3. Apparatus as set forth in claim 1 wherein each of said forming elements is mounted for pivotal movement along a radial path.
 4. Apparatus as set forth in claim 1 wherein the faces of said opposed tool means are substantially vertical in said second position.
 5. Apparatus as set forth in claim 1 wherein said opposed tool means are independently mounted for pivotal movement about spaced pivot points having a vertical spacing about equal to the thickness of said blank and a horizontal spacing about equal to the depth of the convolutions formed in said blank.
 6. Apparatus as set forth in claim 1 wherein said means for urging said opposed tool means toward each other comprises hydraulic actuating means. 